Driving mechanism for flat-form printing machines



May s, 1928.

W. ROCKSTROH DRIVING MECHANISM FOR FLAT FORM, PRINTING MACHINES Filed Aug. 31 1927 2 Sheets-Shea- 1 /nuentor:

VV, Pot/bird! Mays, 1928.

' W. ROCKSTROH DRIVING MECfiANISM FOR FLAT FORM PRINTING MACHINES Filed Aug. 31 1927 2 Sheets-Sheet 2 Muenzar: W R o c Ks fr 0 2 Patented May 8, 1928.

UNITED" STATES PATENT OFFICE.

WALTER ROCKSTROI'I, F POSTELWITZ, GERMANY.

I Application filed August 31, 1927,5eria1 No. 216,746, and in Germany September 21, 1926.

This invention relates to fiat-form or flatbed printing presses.

In printing presses with reciprocating carriages and an intermittently driven print- 5 ing cylinder either turning continually in one direction or oscillating, two kinds of driving mechanism for the carriage are used and a most" exclusively known. The first kind is characterized by a crank mechanism, the cross head of which is a toothed wheel which engages in a toothed bar on the underframe and in a toothed bar on the carriage and effects the reciprocating movement of the carriage; the printing cylinder is provided in front with toothed wheels in which toothed bars on the carriage engage and thereby effect the rotating movement of the printing cylinder. The second kind of driving mechanism is characterized by a separate carriage drive and by a separate printing cylinder drive and is used exclusively in the so-called two-revolution printing presses. The object of the present invention is to simplify the construction of the driving mechanism for fiat-bed printing presses to substantially shorten the machine and. consequently to reduce the cost of construction. Furthermore by the provision of a rib pass ing through the whole breadth and height of the carriage track a machine of high printing capacity is produced with the use of very little material. These special features are achieved by ensuring that the periodical change in the direction of rotation of the printing cylinder actuating the carriage is brought about and effected by means of coupling members that in the deadpoint position of the carriage are switched from left hand turning to right hand. turning and vice versa. V

One embodiment of the invention is shown by way of example in the accompanying drawing in which 7 Fig. 1 is an elevation and Fig. 2 is a plan View.

The actuating'motor a drives a coupling Z) directly in one direction of rotation and a similar coupling 0 indirectly by means of an interposed toothed wheel d in the op-v posite direction. Both couplings have a common shaft 0. Magnetic couplings of the usual kind are, for example, used. The

switching in of the coupling at the dead point positions of the carriage is effected alternately by switches '1' and s, which are connected by a rod t. On reaching the front dead-point position of thecarriage k, the

By means of the toothed wheels 7', g, h, 2', the .3'

cylinder Z is driven. The toothed wheels m mounted at the ends of the printing cylinder are in engagement with toothed bars at on the carriage la and impart a reciprocating movement to the carriage. V

In addition to a saving in weight, this arrangement has the special advantage that the carriage track 0 over its whole breadth and height can be stiffened by means of a rib p, which cannot be fitted in the case of the classes of driving mechanism hereinbefore referred to. A machine according to the invention has therefore greater stability without any increase in material.

lVhat I claim is z- 1. In a fiat-bed printing press-comprising a driven printing cylinder and a reciprocating carriage actuated therefrom, the combination with the cylinder driving mechanism of alternative coupling members, and changeover means actuated when the dead-points in.

the carriage travel are reached to change overthe cylinder drive through said members;

2. In a flat-bed printing press comprising nation with the cylinder driving mechanism. 7

of alternativeelectrical coupling members in the cylinder drive, and means actuated by the carriage when. it reaches its dead point positions to switch over the drive from on coupling member to the other.

4.. A'flat-bed printing press comprising a printing cylinder, means including a coupling member for driving said cylinder in one direction, means including a second coupling membcr for driving said cylinder in the opposite direction,a reciprocating carriage, means for actuating said carriage from said cylinder, and means actuated as said carriage reaches each of its dead point positions for rendering one coupling member ineffective and rendering the other coir pling member effective.

5. A flat-bed printing press comprising a printing cylinder, means including a coupling member for driving said cylinder in one. direction, means including a second cou pling member for driving said cylinder in the opposite direction, a reciprocating carriage, means for actuating said carriage from said cylinder, and means actuated by said carriage as it reaches its dead point positions for rendering the active coupling member inactive and rendering the inactive coupling member active.

lVALTER ROCKSTROH. 

